This application is related to Japanese Application No. H11-287031, filed Oct. 7, 1999, the disclosure of which is herein incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to passenger protecting devices having an airbag and an air belt that are inflated when a vehicle crashes, and, more particularly, to passenger protection devices controlling the amount of inflating gas generated in each in accordance with a crash impact scale.
2. Description of the Related Art
Seat belt assemblies and airbag devices are used in vehicles such as automobiles, for protecting passengers. When the vehicle crashes, a seat belt locking mechanism is activated to prevent the seat belt from being further extended. Additionally, an inflator of the airbag device is activated to inflate the airbag. Also, various types of air belt assemblies for inflating a portion of a seat belt have been proposed recently.
Japanese Unexamined Patent Publication No. 5-85301 describes an example of an air belt assembly. FIG. 3 is a perspective view showing the air belt assembly of this publication. This air belt assembly 1 includes an air belt 2, a webbing 2a, a lap belt 3, a buckle device 4, a tongue 5, and a through anchor 6. The air belt 2 extends over a passenger""s body diagonally from the right side to the left side. The webbing 2a is coupled to the air belt 2. The lap belt 3 extends over the passenger""s body from the right side to the left side. The buckle device 4 is secured to, for example, the vehicle""s floor. The tongue 5 is inserted in the buckle device 4 when the belts are fastened. The through anchor 6 guides the webbing 2a. 
The webbing 2a is formed by a normal type belt like a typical, prior art seat belt and is slidably guided by the through anchor 6. An end of the webbing 2a is secured to a seat belt retractor having an emergency locking mechanism (ELR) 7 fixed to the vehicle body. The retractor 7 thus retracts the webbing 2a. An end of the air belt 2 is connected to the webbing 2a through, for example, sawing, and the other end of the air belt 2 is connected to the tongue 5.
The lap belt 3 is formed by a normal type belt like a typical seat belt. An end of the lap belt 3 is connected to the tongue 5, and the other end of the lap belt 3 is connected to a seat belt retractor (ELR) 8 secured to the vehicle body. A gas generator 9 is coupled to the buckle device 4 and is activated to generate high pressure gas in case of an emergency such as a car crash. A passage extends in the tongue 5 and the buckle device 4 for introducing gas from the gas generator 9 to the air belt 2.
The air belt 2 is formed by a belt-like bag having a relatively large width, which is folded to reduce its width and is encompassed by a cover. The air belt 2 is normally maintained in a belt-like shape. The air belt assembly 1 is used in the same manner as a prior art seat belt assembly. If the gas generator 9 is activated due to, for example, a car crash, the air belt 2 is expanded to protect the passenger, as indicated by the dotted lines.
Japanese Unexamined Patent Publication No. 11-78769 describes a passenger protection device detecting an impact scale during a crash with an acceleration sensor. An acceleration, an acceleration level, an acceleration change, and a decreased speed amount are determined through a control circuit, and the impact scale is thus detected. The amount of the gas generated by an inflator of the airbag device is controlled in accordance with the impact scale. Further, Japanese Unexamined Patent Publication No. 11-170948 describes a passenger protecting device having an airbag and an air belt that remains non-inflated if the vehicle speed is relatively small when a crash occurs. Instead, the device restrains a passenger only with an air belt, which functions simply as a seat belt. If the vehicle speed is intermediate when a crash occurs, the device inflates only the air belt. Further, if the vehicle speed is relatively large when a crash occurs, the device inflates both the airbag and the air belt.
It is an objective of the present invention to provide a passenger protection device that controls the amount of the gas generated for inflating an air belt, as well as the amount of the gas generated for inflating an airbag, in accordance with a detected impact scale of a crash under different crash scenarios.
A passenger protection device of the present invention has an airbag device having an airbag and an airbag gas generator for inflating the airbag by supplying gas to the interior of the airbag and located forward of a vehicle passenger, an air belt assembly having an inflating portion and an air-belt gas generator inflating the inflating portion by supplying gas to the interior of the inflating portion, and a control unit controlling the airbag gas generator and the air-belt gas generator in response to a crash of the vehicle. The passenger protecting device is characterized in that the amount of gas generated by the air-belt gas generator is adjustable and that the control unit operates to increase the amount of gas generated by the air-belt gas generator in accordance with an increase of an impact caused by the crash.
In this passenger protection device, when the impact scale is relatively small, or when restraint for the passenger need not be increased, a decreased amount of gas is supplied to the air belt such that the passenger is received by the air belt that is expanded loosely. When the impact scale is relatively large, an increased amount of gas is supplied to the air belt such that the passenger is restrained by the air belt that is expanded tightly. This sufficiently absorbs the shock acting on the passenger.
In the passenger protecting device of the present invention, it is preferred that the gas generating amount of the airbag gas generator, as well as that of the air-belt gas generator, is increased in accordance with an increase of the crash impact scale. Accordingly, if the impact scale is relatively small, a decreased amount of gas is supplied to the airbag such that the passenger is received by the airbag that is expanded loosely. However, if the impact scale is relatively large, an increased amount of gas is supplied to the airbag such that the passenger is reliably received by the airbag when hitting the airbag at a relatively high speed.
In the present invention, the gas generating amount of each gas generator may be increased continuously. However, if the gas generating amount is increased in a stepped manner, the manufacturing cost of the device can be reduced.
In the present invention, a weight detecting means may be provided for detecting the weight of the passenger seated in the vehicle. The control unit operates to increase the gas generating amount of at least the air-belt gas generator or the airbag gas generator in accordance with an increase of the weight detected by the weight detecting means.
In this structure, the gas generating amount of the gas generator is controlled in accordance with not only the crash impact scale but also the passenger""s weight. Thus, when the impact scale is relatively small, the passenger is received by the loosely expanded airbag or air belt as necessary. Further, when the impact scale is relatively large, an increased shock is absorbed.
The crash impact scale is detected, for example, in relation to an acceleration change determined by detecting an acceleration (deceleration) applied to a vehicle as time elapsed from the time at which the crash occurs.